Abstract: The along and perpendicular rails of a received signal (e.g., modulated using multi-phase shift keying) are rotated to compensate for frequency offsets between the carrier frequency of the received signal and the reference frequency of the local oscillator. The rotation angles are updated, based on the rotated along rail, during dotting sequences in the received signal. In one implementation, the dotting sequences are detected based on the rotated perpendicular rail. The beginnings of dotting sequences are detected by thresholding the average on the perpendicular rail, and the ends of dotting sequences are detected by analyzing the encoded data for non-dotting-sequence values. In a cordless phone application, different dotting sequences may be used to distinguish base-to-handset transmissions from handset-to-base transmissions.

Abstract: In an optical arrangement for amplifying an input lightwave signal by a predetermined amount to a desired output level, an optical amplifier is connected to a loss element. The optical amplifier is pumped by an amount exceeding a nominal amount wherein the nominal amount is the amount of pumping needed to attain the desired output level at the optical amplifier output. By attenuating the signal output from the optical amplifier, the loss element generates an output signal from the optical arrangement at the desired output level. This optical arrangement is characterized by an improved noise performance (noise figure) over standard optical amplifiers.

Abstract: Improved side mode suppression with significantly reduced side mode suppression ratio fluctuation during laser tuning is realized in a distributed Bragg reflector laser structure by incorporating at least one reflector element which exhibits an asymmetric reflection characteristic versus wavelength over a band of wavelengths wide enough to include at least two longitudinal modes of the laser. That is, the asymmetric characteristic is wider than the mode separation for adjacent longitudinal modes of the laser. In one embodiment, a distributed Bragg reflector laser is shown wherein the Bragg reflector includes a corrugated waveguides with corrugations having a period which varies nonlinearly from .LAMBDA..sub.O at one end of the reflector to .LAMBDA.hd L at the opposite end of the reflector, where .LAMBDA..sub.O is greater than .LAMBDA..sub.L. Integrated and extended cavity or hybrid structures are described in both semiconductor and fiber laser structures.

Abstract: A wavelength tunable optical filter having a characteristic single transmission peak for enhanced tunability comprises a phase control section positioned between a Distributed Bragg Reflector section and a high reflectivity mirror. The Distributed Bragg Reflector section comprises a periodic region grating positioned over an end portion of a passive waveguide whereas the phase control section comprises the portion of the passive waveguide region located between the grating and the mirror. Continuous tunability in the range of several THz may be achieved by controlling the refractive index in either the phase control or distributed Bragg reflector section. The optical filter is expected to have a frequency switching time of a few nanoseconds and, thus, is applicable to both transmission and switching applications.

Abstract: The present invention relates to packet switched interconnection protocols for use in high-speed optical Star-configured Local Area Networks (LANs). In the present Star LAN, a plurality of N+1 wavelength division multiplexed (WDM) channels are provided for use by M transceivers connected to the Star coupler, where preferably M>N. N of the N+1 WDM channels are used for transmission of data packets, and the remaining WDM channel is used by all transceivers for transmitting control packets only. In the present protocols, a transmitter in an active transceiver first send a control packet over the control channel using a first protocol such as, for example, ALOHA or CSMA. The control packet includes (1) the transmitter's unique address, (2) the destined receiver's address, and (3) the address of the data channel to be used in transmitting the associated data packet.